version librdkafka used by Stackage

[juhp]

I am updating the Stackage Nightly build image and wonder if the version of librdkafka is still correct?

(Actually it seems we never enabled your testsuite in Stackage after adding the library 😢)

https://github.com/commercialhaskell/stackage/blob/master/docker/03-custom-install.sh#L73

cc @AlexeyRaga

[juhp]

If possible we could just use the Ubuntu package perhaps?

https://packages.ubuntu.com/search?keywords=librdkafka-dev

but it is up to you really.

[AlexeyRaga]

Hmm.. Maybe... I don't use stackage TBH, and, perhaps, at that time there was no ubuntu package?
I'd say yes, we should be able to use the ubuntu package now.

[gbaz]

actually, what versions of librdkafka is this tested against? it looks like the version tag in the script (which i made a pr against here) isn't really used for anything? #207